Follow the Ghost. I have 4 Magnum .91 four strokes and use 15% nitro with 20% oil (Ritches Brew). I use this on all my 2 strokes also. Saito advised me on this fuel some time ago for my Saito 65 and I went with it on everything and have always been happy with the results. The nipple on the crankcase is connected to the fuel intake manifold pipe above the carb with the small flexible tubing included. The nipple on the muffler is for the pressure line to the tank. The nipple on the carb just above the needle valve is the fuel inlet from the tank.